The present invention is directed to a turf aerator and more specifically to an aerator having three separate shafts in axial alignment with each other with the tine assemblies on the middle shaft being mounted for free wheel rotation and the tine assemblies on the left and right shafts being mounted for rotation with the left and right shafts which may be selectively driven or simultaneously driven.
Core-type aerators are well known in the art and are generally comprised of a walk-behind unit having a main frame with an internal combustion engine mounted on the top thereof. A transverse shaft is rotatably mounted adjacent a lower rear portion of the frame and has a plurality of discs secured thereto which in turn support a plurality of radially extending core tines. A suitable drive arrangement is provided between the output shaft of the motor and the tine carrying shaft. A pair of adjustable wheels are pivotally mounted on opposite sides of the frame adjacent the rear thereof which may be adjustable in height under the control of an operator walking behind the aerator. Suitable controls are provided on the handle for controlling the drive to the shaft carrying the core tines. In most models of turf aerators, all of the tine carrying discs are simultaneously rotated since they are mounted on a single transverse shaft to which the drive is imparted. At least one turf aerator model is provided wherein the outermost tine carrying discs are mounted on the shaft for a free wheeling operation.
The aerator disclosed in U.S. Pat. No. 6,102,129 is of the walk behind type and which is provided with two independent tine carrying shafts which are axially aligned with each other for independent rotation relative to each other. Each shaft is selectively connected to an output shaft of a motor mounted on the frame of the aerator by two separate drive trains each having a clutch arrangement therein. A pair of control levers are mounted on a handle assembly for operating the clutches in each drive train. Thus either or both of the tine carrying shafts may be rotated to facilitate a turning operation of the aerator or while traversing a sloping surface.
The aerator disclosed in U.S. Pat. No. 5,680,903 is provided with a series of tine assemblies spaced along a driven shaft driven by a motor. Each tine assembly has a plurality of tines for aeration extending in a substantially radial pattern about the driven shaft. The inner tine assemblies along the middle portion of the driven shaft are secured to the driven shaft to drive the aerator along the lawn as the driven shaft rotates. The outer tine assemblies adjacent the ends of the driven shaft are rotatably mounted on the driven shaft. This permits the outer tine assemblies to free wheel independently and thereby make the aerator more maneuverable and easier to turn.